P. Woodland, J. Odell, V. Valtchev, and S. Young. Proceedings of the 1994 IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP), 2, page 125-128. Adelaide, Australia, (April 1994)
C. Laughman, H. Qiao, D. Burns, and S. Bortoff. Proceedings of the 16th International Refrigeration and Air Conditioning Conference, Purdue University, (2016)